Implement limiter flush for handling buffered data remaining at eof.

Signed-off-by: Stefan Westerfeld <stefan@space.twc.de>

src/TODO

 possible improvements:
 - dynamic bit strength
-
-limiter:
-- flush

src/limiter.cc

@@ -97,3 +97,21 @@ Limiter::debug_scale (float scale)
 
   debug_scale_samples++;
 }
+
+vector<float>
+Limiter::flush()
+{
+  vector<float> out;
+  vector<float> zblock (1024 * n_channels);
+
+  size_t todo = buffer.size();
+  while (todo > 0)
+    {
+      vector<float> block = process (zblock);
+      if (block.size() > todo)
+        block.resize (todo);
+      out.insert (out.end(), block.begin(), block.end());
+      todo -= block.size();
+    }
+  return out;
+}

src/limiter.hh

@@ -13,6 +13,7 @@ class Limiter
   uint  block_size        = 0;
   uint  n_channels        = 0;
   uint  sample_rate       = 0;
+  size_t buffered_frames  = 0;
 
   std::vector<float> buffer;
   void process_block (const float *in, float *out);
@@ -25,6 +26,7 @@ public:
   void set_ceiling (float ceiling);
 
   std::vector<float> process (const std::vector<float>& samples);
+  std::vector<float> flush();
 };
 
 #endif /* AUDIOWMARK_LIMITER_HH */

src/testlimiter.cc

@@ -69,7 +69,10 @@ impulses()
       in_all.insert (in_all.end(), in_samples.begin(), in_samples.end());
       out_all.insert (out_all.end(), out_samples.begin(), out_samples.end());
     }
-  for (size_t i = 0; i < min (in_all.size(), out_all.size()); i += 2)
+  vector<float> out_samples = limiter.flush();
+  out_all.insert (out_all.end(), out_samples.begin(), out_samples.end());
+  assert (in_all.size() == out_all.size());
+  for (size_t i = 0; i < out_all.size(); i += 2)
     {
       assert (out_all[i] == out_all[i + 1]); /* stereo */
       printf ("%f %f\n", in_all[i], out_all[i]);
@@ -114,4 +117,6 @@ main (int argc, char **argv)
       out.write_frames (out_samples);
     }
   while (in_samples.size());
+
+  out.write_frames (limiter.flush());
 }